JPS61226650A - Method and instrument for measuring moisture - Google Patents

Abstract

PURPOSE:To make possible the easy quantitative determination of moisture with high accuracy and high exactness by removing the influence of the coexisting component except the moisture. CONSTITUTION:The figure is a graph indicating the relation among the output signal MH corresponding to the moisture concn. of a moisture sensor 23, the signal RH corresponding to the co-existing component concn., the signal MO corresponding to the moisture concn. of a comparating sensor 24 and the signal RO corresponding to the co-existing component concn. The output at the moisture sensor 23 appears actually as (MH+MO); on the other hand, the output at the comparing sensor appears as (RH+RO). (MH+MO)-k.(RH+RO)=MH-k.RH is obtd. if MO/RO (the ratio of the magnitude of the signal with respect to the co-existing component) is known k. MO is canceled from the output A by subtracting the k-times of the output B of the sensor 24 from the output A of the sensor 23. The quantitative determination of the moisture concn. is made possible while the influence of the co-existing component is removed in accordance with the subtracted value by setting preliminarily the detection line.

Description

[Detailed description of the invention] (b) Industrial application field The present invention relates to a moisture measuring method and apparatus.

More specifically, it is possible to measure moisture contained in various gaseous and liquid samples with high precision and accuracy, such as process gas for the petrochemical industry, recycled gas from oil refinery plants, high-pressure cylinders, organic solvents, petroleum, etc. The water concentration in
In particular, the present invention relates to a moisture measuring method and device suitable for detecting trace amounts of moisture concentration.

(b) Prior art Conventional methods for quantifying the concentration of water in various media, especially gases and liquids, include the Karl Fischer method, gas chromatography, and methods for determining water content based on physical changes such as resistance, electric capacity, and weight due to water adsorption. Methods that use moisture (humidity) sensors to detect moisture (humidity) and methods that detect weight changes due to infrared heating are selected and put into practice depending on the application.

The reality is that the substance water, along with oxygen, air, carbon dioxide, etc., has an important role in human life, both directly and indirectly. ) are indispensable. Therefore, the fields in which moisture measurement is required are extremely wide-ranging. For example, it is classified into solid moisture measurement, liquid moisture measurement, and gas moisture measurement based on ``what kind of substance is the moisture measurement being used for'', and also ``for what purpose is the moisture measurement being used''? It is classified into environmental measurement, soil moisture measurement 11 food moisture measurement, and so on.

On the other hand, it is preferable to use a total method or a measuring device that can be applied to all kinds of applications, and (1) can measure moisture in any state, and (2) can measure moisture at any moisture content. There are demands for accurate analysis, (3) simple measurement operations, and (4) short measurement time, but in reality, the substance water is chemically extremely active and resistant to other substances. Due to the complex coexistence relationship between the two, there is currently no ideal method.

However, in order to meet these intense needs, various methods have been devised, starting with hair thermometers in the past, and each method is used depending on the intended purpose. can be said to be the current situation.

In this regard, the current state of the art will be described in some detail, emphasizing the scope to which the present invention pertains.

First, as a method for measuring moisture in a liquid, the Karl Fischer method (hereinafter referred to as the KF method) is used with great reliability. This method is basically a method in which a liquid containing water is titrated using an expensive and complicated liquid reagent called a KF reagent, and the water content is analyzed volumetrically. Since the titration operation is required, it takes at least 30 minutes for one analysis, and the KF reagent itself absorbs moisture from the atmosphere during the titration operation, which is prone to errors and requires special consideration and skill in the analysis operation. It is well known that this requires As mentioned above, the KF method is originally a method for measuring moisture in liquids, but to measure moisture in gases, a sample gas containing water is absorbed into a fixed amount of reagent (for example, by bubbling mixing), and then titration is performed. In addition, when measuring moisture in solids, the sample solid is heated and vaporized.
Furthermore, it is well known that titration is performed by absorption into a liquid.

On the other hand, there are many methods that avoid complicated operations such as titration and instead measure moisture by simply bringing a sensor into contact with the sample. As such a moisture sensor, a so-called electric resistance type, capacitance type, or piezoelectric type moisture (or humidity) sensor that uses a ceramic plate or a polymer electrolyte membrane as a humidity sensitive substance is applied. There are various types of such sensors, but in reality they cannot be widely applied to all applications, and are only applied for limited purposes and applications after fully understanding the characteristics of the sensor. is the current situation. For example, with regard to the influence of coexisting substances in a sample, it is possible to measure only a large amount of water with a negligible influence, so it cannot be used for trace moisture measurements, but it can be used for large quantity measurements such as atmospheric moisture measurements. It will be possible.

In this way, it is desirable for a moisture sensor to have the ideal performance of being sensitive only to moisture and not at all to other coexisting components, but in reality, such a moisture sensor has not been found. However, it is highly unlikely that this will ever happen. In practice, sensors are sensitive to coexisting components other than moisture, especially organic solvent components, but sensors with selectively superior sensitivity to moisture are inevitably used. Therefore, in the moisture measurement method using a normal moisture sensor, the influence of coexisting components on the measured value is an extremely important issue, and for this reason, it is necessary to limit the application and limit the range in which moisture can be measured.
This makes accurate measurement of trace moisture impossible. In particular, when measuring trace amounts of water in liquids, it is important to be accurate, as this involves detecting trace amounts of water in substances that coexist in large amounts. In addition, there was a problem in that it was extremely difficult to obtain reproducible measured values in a short period of time.

(c) Purpose of the Invention The present invention has been made to solve these problems, and in particular, it provides a moisture measurement method that eliminates the influence of coexisting components other than moisture and easily performs moisture determination with high precision and accuracy. The present invention seeks to provide methods and apparatus.

In view of the importance of moisture measurement, the inventor of the present invention has repeatedly considered universality of application as much as possible, and has conducted intensive research into new methods and devices based on experimental research.As a result, the inventor has come up with a special differential measurement method. In addition to improving measurement precision and accuracy by carefully removing the influence of coexisting substances, KF is also capable of quantifying trace amounts of water in liquids (especially in organic solvents).
We have developed a method that is more than 10 times more sensitive than conventional methods.

The details will be described later, but the gist will be summarized below. The present invention focuses on the ease of use of various moisture sensors, and allows for measurement while allowing the influence of coexisting substances that moisture sensors have (i.e., sensitivity to coexisting substances that cannot be avoided). The result is a method that can be performed with accurate, precise and sensitive measurements, excluding its negative effects. In other words, two sensors with similar structures and similar sensitivities to coexisting substances are prepared, and the sensitivity to water is adjusted to be especially advantageous by introducing a hydrophilic group into only one of the sensors. are brought into contact with the test sample at the same time.

At this time, the degree of influence of the coexisting substances on both sensors changes by adjusting the loading of hydrophilic groups, etc. However, by studying the nature of the output signals from both sensors and using clever calculation processing, it is possible to They found a way to exclude the negative effects of coexisting substances. As a result, we have actually confirmed that it is possible to precisely measure trace amounts of water, such as 0.2μ9, contained in a single-produced organic solvent using a vaporizer.

(d) Structure of the Invention Thus, according to the present invention, a sample gas consisting of a gas sample or a vaporized sample has (a) sensitivity to coexisting components other than moisture, but a sensitivity that is selectively superior to moisture; When measuring moisture by bringing the sample gas into contact with the moisture sensor (a),
(b) Contact a comparison sensor that is sensitive to coexisting components other than moisture and does not have selectively superior sensitivity to moisture, and the output A of the moisture sensor (a) and the output B of the comparison sensor (b) are lowered. Formula: (In the formula, the value of k is the intensity ratio between the sensitivity of the moisture sensor (a) to the coexisting components and the sensitivity of the comparison sensor (b) to the coexisting components.) A moisture measurement method is provided, which is characterized by quantifying moisture in gas. Further, according to the present invention, a moisture measuring device suitable for carrying out the above method is provided.

The most distinctive feature of this invention is the conventional moisture sensor (a).
and the above-mentioned comparison sensor (b>) are used to perform quantification by removing at least the output based on coexisting components.This makes it possible to easily and highly accurately quantify moisture. According to the water droplet, 0.2μQ in liquid sample 14
The conventional Karl Fischer method (
This is significantly improved compared to the detection limit of about 10 μg for sample 14, and the analysis time is also significantly shortened to about 2 to 3 minutes.

As the above-mentioned moisture sensor (a), various conventionally known moisture sensors can be used. Usually, a moisture sensor having a polymer membrane into which a hydrophilic group is introduced, that is, a polymer electrolyte, as a moisture-sensitive membrane is used. Are suitable. On the other hand, as comparative sensor +b), moisture sensor (a) except that it has a polymer membrane in which hydrophilic groups are reduced or substantially not introduced
It is possible to use a device having a similar configuration. As the polymer membrane, known ones such as polystyrene, styrene-divinylbenzene copolymer, cellulose polymer, etc. can be used, and as the hydrophilic group, known ones such as sulfonate group, phosphonate group, quaternary ammonium group, etc. can be used. is applicable. Moisture sensor (a) usually has a moisture-sensitive membrane that uses a plasma-polymerized organic polymer membrane as the polymer membrane and has a sulfonate group or quaternary ammonium group introduced into its surface layer, and a comparative sensor that has a plasma-polymerized organic polymer membrane. (a)
It is also preferable to use them in combination. It is more preferable to use a sensor configured as an oscillation frequency detection type sensor using a piezoelectric element in order to improve the sensitivity and precision of measurement. Such a sensor is disclosed in, for example, Japanese Patent Application Laid-Open No. 59-242.
It can be produced according to the description in Publication No. 34.

The principle of removing the output of coexisting components using the above-mentioned moisture sensor (a) and the comparative sensor will be described below with reference to FIG.

FIG. 1 shows an output signal MH corresponding to the moisture concentration of the moisture sensor (a), a signal RH corresponding to the coexisting component concentration, a signal M corresponding to the moisture concentration of the comparison sensor (b+), and a signal corresponding to the coexisting component concentration. This is a graph showing the relationship between Ro.The output from the moisture sensor (a) is actually (MH+M
O), while the output at the comparison sensor is (R
)-1+RL+). Here Mo/Ro
If (ratio of signal magnitudes for coexisting components) is known, then (MH−+ +Mo ) −k ・(RH
+Ro) -MH- becomes -RH, and the moisture sensor (
Mo is canceled from the output A by subtracting twice the output B of the comparison sensor (to) from the output A of a). At this time, the output corresponding to moisture is the output of the moisture sensor (a) by subtraction. The original signal size M
However, the A-k and B values are proportional to the water concentration, so by setting a calibration curve in advance, it is possible to calculate the influence of coexisting components based on the subtracted value. It becomes possible to quantify the moisture concentration in the measurement gas, and in turn, in the gas sample or vaporized sample, while removing it.

In actual problems, the coexisting interfering substances are not a single substance but multiple components, and each component of the multiple components varies arbitrarily, making it impossible to quantify trace amounts of water. However, the measurement method based on the present invention The effect is remarkable when there are multiple coexisting substances rather than just one, and it is especially useful for quantifying the trace water concentration present in a test sample with multiple organic solvent components whose types and composition ratios are unknown. . At this time, even if the output signals of the sensor corresponding to the concentrations of each of the plurality of coexisting components are different, no problem substantially occurs. For example, when measuring moisture, if acetone and ethyl alcohol coexist in the sample gas, even if the magnitude of the output signals of both sensors for acetone and the output signal for ethyl alcohol are different, the value will not be the same. If they are the same, the above subtraction output is (MH+Ms +M2)-k ('RH+Rt\゛R
2) (In the formula, Ml and Ri are the outputs of the moisture sensor and comparison sensor for acetone, Ml and R2 are the outputs of the moisture sensor and comparison sensor for ethyl alcohol), and the overall signal is (M)- 1-kRH), and the influence of coexisting substances can be ideally removed. In fact, the values for various organic solvents are based on the examples (see Table 1) described later for moisture sensors with polymer membranes and comparative sensors.
It was found that the effect of coexisting components can be virtually eliminated in these combinations, and
Highly accurate and accurate measurements are possible. For various expected coexisting components, this value has a constant value, but even if the coexisting components have slightly different values,
Although it is not ideal, there is no doubt that it significantly reduces measurement errors.

(E) Example As a moisture sensor, a piezoelectric moisture sensor was used, which was equipped with a moisture-sensitive membrane in which a sulfonate group was introduced into a polystyrene membrane.

This moisture sensor is based on Japanese Patent Application Laid-Open No. 59-24234, in which gold electrodes are deposited on both sides of an AT-cut crystal plate with an oscillation frequency of 9 MHz, and a polystyrene film is formed by plasma polymerization on the gold deposited film in styrene vapor. , which was obtained by introducing sulfonate groups into the polystyrene membrane by leaving it in an anhydrous sulfuric acid gas atmosphere.
It is a crystal oscillator with a thickness of 0.81I17 and a moisture sensitive film thickness of 0.1 μm.

On the other hand, as a comparison sensor, a piezoelectric element plate covered with polystyrene and having the same structure except for the step of introducing the sulfonate group was used.

Table 1 shows the results of measuring the individual sensitivities of the above-mentioned moisture sensors and comparative sensors to moisture and various organic solvents (coexisting components), and the sensitivity ratios of the sensors for each of these components.

(The following margins continue on the next page.) Table 1 (The sensitivity values above are the relative values of the output when each sensor is vaporized and brought into contact with the water.) The sensor is sensitive to coexisting components other than moisture, but has a selectively dominant sensitivity to moisture, while the comparative sensor is sensitive to moisture and coexisting components, but has a selective sensitivity to moisture. It has no gender. Furthermore, the sensitivity ratio k (the intensity ratio between the sensitivity of the moisture sensor to the coexisting component and the sensitivity of the comparison sensor to the coexisting component) is also approximately constant, and it is understood that it is sufficient to set it to about 3.0 for the organic solvent component.

The output A of the moisture sensor for a sample containing each of the above components by 1 is 2145 (change in oscillation frequency, unit: H)
2) and the output B of the comparison sensor is 68, so the subtracted output A- and -B become 1941. For example, add 0.5 d of water, 24 d of ethyl alcohol, and 0.0 d of acetone.
5J, benzene 0.5. J, Gasoline 14, Freon-
The output A of the moisture sensor for the reagent containing 111, All is 1196.7, and the output of the comparison sensor is 15
．． 5, and the subtraction output is 91.0.

Therefore, it can be seen that the sample gas containing 1 A of water has half the value of the sample gas containing 0.54 water, and that even if the types and ratios of the coexisting components vary, highly precise and accurate measurements are possible.

FIG. 2 is a configuration explanatory diagram showing an embodiment of the apparatus of the present invention. In the figure, the moisture analyzer (1) includes a moisture measurement cell (2) that incorporates the moisture sensor and comparison sensor (c) described above, and is equipped with a sample gas inlet 21) and an exhaust port.
A sample gas flow path (3) that can supply sample gas, and a calculation section (
It basically consists of 4). The calculation unit (4) includes a transmission circuit (41) for each sensor and sensor.
'), oscillation frequency conversion amplifier (42) (42')
and a control cell (4
3) (43') are provided, and the amplified outputs thereof are subtracted by a differential operational amplifier (44), converted to water concentration, and displayed. Here, the amplification factor of the comparison sensor (amplifier (42') on the second slope side) is adjusted to be three times the amplification factor of the moisture sensor (to) in accordance with the above-described embodiment.

The sample gas flow path (3) is equipped with a vaporizer (31) and a carrier gas (N2 gas) supply pipe diagram for transferring the vaporized sample into the cell (a, vaporization marked 3) up to 200°C. Capillary tube equipped with heating means (
311), and the liquid sample is introduced into the vaporizer via an injection can. The introduced liquid sample is heated and vaporized, but during this time valves □□□ and (G) are closed. After sufficient vaporization, these are opened and the sample gas is introduced into the cell (2) by the carrier gas. The Rukoto.

The introduced sample gas comes into contact with the sensor (support) 4 and then is discharged to the drain, but in the calculation section (4), the output of the sensor @ 2 gradient is subtracted from the output A- to -B (k is 3) is calculated, and this output is roughly multiplied by the water concentration conversion value to display the water concentration on the display (45). Note that, of course, there is no problem in directly introducing the gas sample into the channel (3).

The results of quantifying trace amounts of water (10-1 to 103 μg) in various organic solvents using the above device F+1) are shown in the third section.
As shown in the figure. It can be seen that excellent linearity is obtained up to the order of 10-1 .mu.9 as described above, which is superior to the Karl Fischer method (limited to about 10 .mu.g), which is considered to be the most reliable conventional method. Furthermore, the time required for the above analysis is approximately 2 to 3 minutes, which is found to be extremely advantageous compared to the Karl Fischer method, which requires 30 minutes or more.

(f) Effects of the Invention According to this invention, it is possible to efficiently remove the influence of coexisting components in the measurement gas other than moisture, and perform high-precision and high-accuracy moisture determination, especially in gas and liquid samples. Quantification of trace amounts of water can be easily carried out. In addition, in the case of liquid samples, analysis operations only require injecting a small amount of 1 to 10 samples using a syringe, compared to the conventional Karl Fischer F! x
It is advantageous compared to the Karl Fischer method (usually requires 100 to 100 xi), and it is roughly superior to the Karl Fischer method in terms of analysis time, detection limits, analyst skill level, measurement accuracy of trace components, etc. It's advantageous. Therefore, it is particularly suitable for measuring the water content in liquid samples such as various organic solvents, petroleum, heat mediums, and the like. For example, 0.5 for one gasoline sample
It can accurately measure the moisture content of μq, and the JIs method (Karl Fischer method) can measure 300hyn of 100xi gasoline.
(3μg of water in 14), and the water content of Freon-11 as a refrigerant is 1.0f.
FW /W or less (10 μQ or less moisture in 10 g sample)
However, according to the present invention, detection is possible with a small amount of sample, and it is sufficient to use ioo and p, for example.

Note that the method of removing the influence of coexisting components in the method of this invention can be applied to sensors for other components, and it is possible to combine a sensor with high sensitivity and a sensor with low sensitivity to the intended test component. As a result, it is expected to be applied to the measurement of substances other than water.

[Brief explanation of the drawing]

FIG. 1 is a graph for explaining the principle of the method of the present invention, FIG. 2 is a configuration explanatory diagram showing an embodiment of the apparatus of the present invention, and FIG. It is a graph illustrating the relationship with water concentration together with a comparative example. (1)...Moisture analyzer, (2...Moisture measurement cell, (3)...Sample gas flow path, (4)
・・・・・・Calculation section, 3υ・・・Sample gas inlet, ＼・・・Sample gas outlet, @・・・・・・・・・
・Moisture sensor, (b)... Comparison sensor. Procedural amendment July 26, 1985 Patent Application No. 67410 of 1985 2 Title of the invention Moisture measuring method and device 3 Relationship to the person making the amendment Patent applicant address 2-jo Kawaramachi-dori, Nakagyo-ku, Kyoto City Lower Roots Funatocho 3
Address 78 Name (199) Shimadzu Corporation Representative Setsuo Yokochi 4, Agent 530 Address 1-3 Quarter, 5-chome Nishitenma, Kita-ku, Osaka
One Bill 5, date of amendment order) 6. Contents of amendment in the "Claims" and "Detailed Description of the Invention" columns of the subject of amendment mtn 7. Correct "anything" to "everything". 2. Correct rRsJ on page 13, line 3 of the same book to rMOj. 3. Correct rMoJ on the 4th line of the same page to rRHj. 4. On the 8th line of the same page, replace Mo/ROJ with “M here.”
H:s Correct with RH Mo/RoJ. 5. On the 14th line of the same page, “Naru.” and [At this time...
・" and "Here, moisture sensor (a) is predominantly sensitive to moisture, and b) is not predominantly sensitive to moisture. In other words, MH>RH, and R)-1 is ignored. .”
Insert. 6. It is reduced by -RH from rMH in lines 5 to 4 from the bottom of the same page, but for A- and -B values, change from "MI-
The 1 value, that is, the (A-k-B) value, is corrected as J. 7. Table 1 on page 17 of the same document is amended as follows. Table 1 8, page 18, line 3 of the same book, f about 3.0"
” he corrected. 9. Correct “2145J” on the 6th line of the same page to f 2048J. 10. Correct “68” on the 7th line of the same page to j 145J. 17, same page, line 8 “1941J 1999.7
Correct it with J. 12, same page line 12 [1196,7J j 106
Correct it to 5.5J. 13, same page line 13 [75,5J 206.5
Correct it with J. 14. Change "97.0" in line 13 of the same page to 999.7
Correct it as j. 15. Correct "14" in line 14 of the same page to r 0.5dJ. 16. Correct rO, 5dJ in line 14 of the same page to "1 loan." 17. "3 times" on page 19, line 12 of the specification is rl/3
Correct it with J. 18, "r(k is 3)" on page 20, line 6 of the same book as r(k
is corrected as 1/3)J. 19. Amend Figure 1 of the drawings as shown in the attached sheet. Claims 1. A sample gas consisting of a gas sample or a vaporized sample is (a)
When measuring moisture by bringing the sample gas into contact with a moisture sensor that is sensitive to coexisting components other than moisture but has selectively superior sensitivity to moisture, the moisture sensor (a)
At the same time, the output A of the moisture sensor (a) and the output of the comparison sensor + b + are For B, the following formula: [In the formula, the value of k is calculated by subtracting the moisture sensor (the intensity ratio of the sensitivity to that coexisting component and the sensitivity to the coexisting component of the comparison sensor (b)), and based on this subtracted output value. A moisture measurement method characterized by quantifying moisture in a sample gas. 2. Moisture sensor (a) is a moisture sensor equipped with a moisture sensitive film made of a polymer film into which hydrophilic groups have been introduced, and comparative sensor) 2. The method for measuring moisture content according to claim 1, wherein the sensor is provided with a polymer film in which moisture content is reduced or substantially not introduced. 3. The moisture measuring method according to claim 2, wherein the coexisting component is a single or mixed organic solvent component, and the k value is set to about 1/3. 4. The moisture measuring method according to any one of claims 1 to 3, which is used to measure trace amounts of moisture present in an organic solvent component. 5. Equipped with a sample gas inlet and an outlet, inside are (a) a moisture sensor that is sensitive to coexisting components other than moisture, but has a selectively superior sensitivity to moisture; a moisture measuring cell equipped with a comparative sensor that is sensitive to moisture and does not have a selectively superior sensitivity to moisture; a sample gas flow path that supplies a sample gas into the moisture measuring cell;
For the output B of the moisture sensor (a) compared with the output A of the moisture sensor (a) when sample gas is supplied, use the following formula: % formula % [In the formula, the value of k is compared with the sensitivity of the moisture sensor (a) to the coexisting components. A moisture measuring device comprising: a calculation section that calculates and displays the moisture concentration by calculating the intensity ratio between the sensitivity and the sensitivity to the coexisting components of the sensor), and multiplying the calculated output value by a moisture concentration conversion value. 6. The moisture sensor according to claim 5, wherein a control sensor and a cell are attached to each of the moisture sensor (a) and the comparison sensor (b>) to make it easier to detect only the change as an output signal. Measuring device. 7. The moisture measuring device according to claim 5, wherein the sample gas flow path is provided with a liquid sample vaporizer and a carrier gas supply section capable of transporting the vaporized sample into the moisture measuring cell. Figure 1

Claims (1)

[Claims] 1. A sample gas consisting of a gas sample or a vaporized sample is (a)
When measuring moisture by bringing the sample gas into contact with a moisture sensor that is sensitive to coexisting components other than moisture but has selectively superior sensitivity to moisture, while bringing the sample gas into contact with the moisture sensor (a),
(b) A comparison sensor that is sensitive to coexisting components other than moisture and does not have a selectively superior sensitivity to moisture is also brought into contact with the output A of the moisture sensor (a) and the output B of the comparison sensor (b). The following formula: A-k・B [In the formula, the value of k is the intensity ratio of the sensitivity of the moisture sensor (a) to the coexisting component and the sensitivity of the comparison sensor (b) to the coexisting component.] A moisture measurement method characterized by quantifying moisture in a sample gas based on an output value. 2. Moisture sensor (a) is a moisture sensor equipped with a moisture sensitive film made of a polymer film into which hydrophilic groups have been introduced, and comparative sensor (b) is a moisture sensor with hydrophilic groups that are compared to moisture sensor (a). 2. The method for measuring moisture content according to claim 1, wherein the sensor is provided with a polymer film in which moisture content is reduced or substantially not introduced. 3. The moisture measuring method according to claim 2, wherein the coexisting component is a single or mixed organic solvent component, and the k value is set to about 3.0. 4. The moisture measuring method according to any one of claims 1 to 3, which is used to measure trace amounts of moisture present in an organic solvent component. 5. Equipped with a sample gas inlet and an outlet, inside of which are (a) a moisture sensor that is sensitive to coexisting components other than moisture but has selectively superior sensitivity to moisture; and (b) coexisting components other than moisture. a moisture measurement cell equipped with a comparison sensor that is sensitive to water and does not have selectively superior sensitivity to moisture; a sample gas flow path capable of supplying a sample gas into the moisture measurement cell;
Regarding the output A of the moisture sensor (a) and the output B of the comparison sensor (b) when sample gas is supplied, use the following formula: A-k・B [In the formula, the value of k is the value for the coexisting component of the moisture sensor (a). a calculation section that calculates and displays the moisture concentration by calculating the intensity ratio between the sensitivity and the sensitivity to the coexisting component of the comparison sensor (b), and multiplying the calculated output value by a moisture concentration conversion value. Device. 6. Moisture according to claim 5, in which each of the moisture sensor (a) and the comparative sensor (b) is provided with a control sensor and a cell for making it easier to detect only the change as an output signal. measuring device. 7. The moisture measuring device according to claim 5, wherein the sample gas flow path is provided with a liquid sample vaporizer and a carrier gas supply section capable of transporting the vaporized sample into the moisture measuring cell.